Apparatus and method for making cable bead

ABSTRACT

A cable bead or grommet is made by rotating an annular metal core, feeding to it substantially undistorted, metal strand and moving the supply of strand successively about the core with respect to an axis passing through its centers of cross sections while confining the path of the supply to avoid straining the strand beyond its resilience limit and synchronizing said moving of the supply with rotation of the core to apply contiguous strands.

United States Patent 11 1 Fraleigh et al.

APPARATUS AND METHOD FOR MAKING CABLE BEAD Inventors: Marion FosterFraleigh, Stow;

Raleigh Warren Wise, Akron, both of Ohio Assignee: Monsanto Company, St.Louis, Mo.

Filed: June 7, 1971 Appl. No.: 150,584

US. Cl. 57/21, 57/158 Int. Cl D02g 3/48 Field of Search 57/1, 9, 2l, 6,158,

References Cited UNITED STATES PATENTS 1/1920 Pratt 57/21 July 31, 19731,414,828 5/1922 mu s7)21 1,415,696 5/1922 Pierce...... 3,130,534 4/1964Osterman 51/9 Primary Examiner-Donald E. Watkins Attorney-Richard O.Zerbe, Larry R. Swaney and Neal E. Willis [5 7 ABSTRACT A cable bead orgrommet is made by rotating an annular metal core, feeding to itsubstantially undistorted, metal strand and moving the supply of strandsuccessively about the core with respect to an axis passing through itscenters of cross sections while confining the path of the supply toavoid straining the strand beyond its resilience limit and synchronizingsaid moving of the supply with rotation of the core to apply contiguousstrands.

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MARION FOSTER FRALEIGH 8| RALEIGH WARREN WISE APPARATUS AND METHOD FORMAKING CABLE BEAD This invention relates to an apparatus and method formaking cable beads or grommets particularly for pneumatic tires.

BACKGROUND OF THE INVENTION Cable beads or grommets comprising anannular core or wire covered by several spirals or convolutions ofstrand wire were described early in the art. A characteristic of thetype of cable bead wherein the core is independent of the spiral wrap orstrands and the strands are smaller in diameter than the core is thatimposition of a bursting stress on the cable will cause the convolutionsof the spiral to grip the core tightly and the uniform distribution ofstress throughout the cable provides great strength. Such beads areespecially desirable for radial tires.

Prior methods of making cable beads have taken various forms butgenerally depart from making beads strictly of the aforesaid type andthereby compromise some of the desirable properties. One method is touse a continuous piece of wire for both the core and strand, the wirebeing wrapped upon itself under sufficient tension to distort it andbend it to lay tightly on the core. Another method is to subject thestrand wire to a precrimping or spiraling operation and then wrap theprespiraled wire without further distortion. Both methods are to anextent self defeating with respect to achieving maximum gripping actionof strand wire upon the core when the bead is subjected to burstingforce.

SUMMARY OF THE INVENTION The method of forming a cable bead according tothis invention comprises supporting and rotating an annular metal coreand feeding substantially untensioned metal strand to the core whilemoving the supply of strand successively about the core with respect toan axis passing through its centers of cross section and confining thepath of the point from which strand is fed to the core so as not tostrain the strand beyond its resilience limit, the speed of theaforesaid motions being synchronized to provide contiguous wrap ofstrand. By substantially untensioned is meant that the tension, if any,is the natural spring tension of the metal strand and is below thatwhich would cause permanent deformation of the strand in applying it tothe core in contrast to a known method wherein the strand isdeliberately subjected to sufficient tension to bend it to lay tightlyon the core.

Preferably the strand applied to the core is substantially undistortedand in any event it is not subjected to precrimping or preforming in thespiral contour it is to assume on the core as in one well knowntechnique. Any permanent curvature is desirably less than the curvatureof the core to which it is applied. Thus, the natural deformationsoccurring in manufacturing and storing strand for furture use canusually be tolerated. Substantially undistorted status desirable forstrand wire fed to the core contemplates normal commercial supplies ofbead wire. However, if the available strand wire has been subjected totoo much strain, it may be treated in known manner to reduce thedistortion before applying it to the core.

On the other hand, preforming may be necessary where otherwise thenatural spring tension of rev to the reel size, the spring tension ofthe wire resists removal from the reel. Wire restrained in a coilapproximately the size of the reel but with a natural tendency to assumelarger coil size also resists removal from the supply due to the springtension of the wire but in this instance the spring force acts againstthe restraining means. As explained hereinafter, selection of thedesired reel size involves a compromise between conflicting principles.

Application of substantially untensioned wire strand to core withoutsubstantial permanent distortion thereof is accomplished by storing asupply of strand in coil form under its own spring tension and confiningthe path of the points from which wire is fed to the core so as not tostrain the wire beyond its ability to recover its original size andshape by providing for discharge of strand from the supply coil atpoints which when outside the plane defined by the circumferentialcenter line of the core are always a perpendicular distance from saidplane less than the radius of the supply coil. Of course, the number ofconvolutions of strand is below the number which would of necessityexceed the resilience limit of the strand. The ideal absence ofpermanent distortion of strand wire is illustrated by removing strandfrom the finished bead and finding that it returns essentially to itsoriginal form. The angle of the strand wire with respect to the plane ofthe core can be varied as desired within the resilience limit of thewire. Permissible limits for wire of given spring characteristics willbe inherently determined by the diameters respectively of the annularcore, of the wire forming the annular core, and of the strand wireitself.

The synchronization provides for starting each successive wrap at adifferent position on the core. The core movement must be a littlefaster than the supply movement because the core must be a littlefurther advanced at the beginning of the next convolution to permit eachsucceeding convolution of strand wrap to lie contiguous to the precedingone. The motion of the supply is therefore synchronized with therotational motion of the core to achieve the desired contiguouscovering, but the strands do not necessarily touch one anotherthroughout their length. Because any error is cumulative with eachsucceeding strand, the synchronizing error is desirably kept below 1percent.

The apparatus for applying the aforesaid principles conveniently mayinclude more or less conventional means for supporting and rotating anannular core, for storing a supply of strand in coiled form and forsynchronizing the speeds of the supply and core movements. The supplymay contain strand sufficient for one or more beads, and it is feasibleto allow somewhat greater length than required and cut the excess at theend, but it is possible to operate with predetermined lengths of strandand thereby avoid cutting strand after wrapping the core.

In one embodiment of the invention a supply of predeterminedlength ofstrand wire is maintained in coil form without deformation except underits own spring tension. The length may be calculated from therelationship Length Circumference multiplied by the times the strand isto be wrapped and multiplied by the secant of the angle of lay withrespect to an axis coincident with the plane of the core. A supply ofstrand in the form of relativly large loops which may approach themaximum which will go through the core avoids preforming the strandsupply and easily provides sufficient strand for one or more beadswithout unacceptable distortion. A disadvantage is that the shorter thelength of strand from the coil to the point where it contacts the core,the greater the angle it subtends as the coiled supply crosses a planecontaining the circumferential centerline of the core and therefore thegreater is the tendency to strain the wire so that a compromise betweenthe conflicting principles must be made. For wrapping in. diameter coreswith nominal 0.06 in. diameter strand, a coil of about 7-8 in. diameteris feasible.

Moreover, another advantage of a relatively large reel is that itfurther minimizes distortion by feeding strand more or less tangent tothe core thereby minimizing the angle formed by the strand and thetangent to the core at the point the strand contacts the core. Forsimilar reasons the strand is desirably fed at approximately the angleof lay which is usually small, say on the order of 3- Accordingly, thepoints from which the strand is fed are desirably kept close to the coreas the strand supply moves about the core. One embodiment for applyingthe aforesaid principle is to subject the coiled supply substantially torectilinear motion in a manner which provides juxtaposition of the coreand supply as the supply moves beside the core.

It will be appreciated that one or several layers of strand may beapplied to the core. Each layer of strand is usually wound opposite thatof the previous layer. According to the usual convention a l 9 cableindicates a core with a single layer of nine strands. Thus, a crosssection of the cable would comprise a central core surrounded by 9strands. Similarly, a l 8 15 cable indicates a central core covered byeight strands and having in addition another layer of 15 strands andfinally an outer layer of 20 strands. The core may comprise single ormultiple units.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an apparatusfor manufacture of a cable bead.

FIG. 2 is a top view of the carriage assembly with the core and strandsupply removed.

FIG. 3 is a side view which illustrates details of the reel and shroud.

FIG. 3a is a cross section of the reel and shroud along line AA of FIG.3.

FIG. 4 is a cross section of an air cylinder for effecting transfer ofthe reel and shroud.

DETAILED DESCRIPTION Referring to FIG. I, the apparatus with the coreand strand in place is illustrated in its condition just prior toactuating the mechanism to start the manufacture of a cable bead. An endof the strand 1 is secured by Mylar tape 2 to the core 3. A supply ofstrand is confined on the reel of reel assembly 4 by shroud 5. The beltdrive clamping cylinder 6 upon actuation brings timing belt 7 intofrictional contact with bead core 3. Upon actuating starting switch 8the core and ensuing bead rotate in the direction of the arrow over sixrubber faced rollers 9, 10, ll, 12, 13 and 14. Grooved guides 15 and 16in conjunction with grooved rotary guides 17 and 18 keep the rotatingbead in a vertical plane. The grooved rotary guides 17 and 18 are heldby spring pressure against the rotating bead. The belt drive assemblywhich drives the bead comprises a frame one side of which 19 is visibleand is pivotally mounted on shaft 20 on which shaft is also mountednotched pulley 21 shown by phantom lines which drives timing belt 7 overthree other notched pulleys 22, 23, 24 and smooth small idler pulleys 25and 26. The belt is pressed against the bead at three points, onebetween the two idler pulleys and at two points on the opposite side ofeach idler pulley through actuation of a clamping cylinder 6, thecontrol switch of which 27 is located in the operators panel 28 togetherwith the starting and stopping switches 8 and 29 for the motor 30. Theclamping cylinder moves the bead drive assembly around the pivot pointwhich comprises shaft 20 thereby bringing the timing belt intofrictional contact with the bead, the idler pulleys thereuponapproaching but not quite contacting the head.

The power is supplied by gear motor 30 which drives large pulley 31 bymeans of timing belt 32 to pulley 33 integral with said large pulley.Large pulley 31 in turn drives a positive variable speed gear box ortransmission 34 by means of timing belt 35 to pulley 36 of the gear box.Another timing belt 37 from the gear box to the bead drive assembly isdriven by the output of the transmission by pulley 38 shown in phantomlines. It transmits power to the bead drive assembly already described.The variable speed gear box serves as a synchronizer by which the ratioof the bead speed to the reel carriage speed can be adjusted asrequired. The gear motor 30 also drives the carriage assembly for thereel by aforesaid timing belt 32 which supplies power to the eccentricdrive 39 at the same time as it transmits power tolarge pulley 31through pulley 33 shown in phantom lines mounted on the same shaft asaforesaid large pulley 31. Thus, both the carriage assembly and bead aredriven from a single power source.

The eccentric moves the carriage assembly back and forth in thedirection of the double arrows. At the extremities of the carriagemotion double acting air cylinder 40 serves as means to shift the reelassembly to the other side of the bead. The reel assembly is mounted onthe inner portion of said double acting air cylinder and is transferredto the inner portion of a second double acting air cylinder (41 of FIG.2) as the direction of motion of the carriage reverses. One of threecarriage drive connecting links 42 is pivotally attached to frame 43;another 44 is pivotally attached to eccentric 39 and both are pivotallyattached to a third carriage drive connecting link 45 which in turn ispivotally connected to a linkage bar (FIG. 2) uniting plate 46 and itscounterpart on which the air cylinders and reel are mounted. A guard 47surrounds the space beyond the frame through which the rods of thecarriage move to prevent injury from too close proximity to themechanism. Cam 48 engages microswitches 49 and 50, one of which at onelimit of the carriage movement actuates air cylinder 40. Rod on one sideof the carriage assembly is secured to plate 61 by short studs (See FIG.2) on which plate air cylinder 40 is mounted. Two slotted bearings whichsupport one side of the carriage assembly are bolted to plate 53 of aframe which supports the carriage assembly. The speed of production iscontrolled by the output to the gear motor, the control 54 for which islocated in panel 28, and the electronic motor controller is in acompartment behind cover 46.

The motion of the reel assembly as it proceeds past the core is shown ingreater detail by the top view of the carriage assembly illustrated inFIG. 2. For greater clarity the carriage assembly is shown with the reeland core removed. The carriage assembly comprises rods 51 and 55,slidably moveable through four slotted bearings 56, 57, 58 and 59, whichbearings are firmly attached to plates 53 and 60 of a frame. Theslidable rods are attached to plates 52, 61 by short rods or spacers andon the plates are mounted air cylinders 40 and 41. The pistons 62 and 63of the air cylinders move in the direction of the double arrows and aregrooved at the ends to receive spring loaded plungers or detents of thereel (FIG. 3). The plates 52 and 61 are joined by rod 64 on which ispivotally mounted linkage arm 45 which transmits the driving force tothe carriage assembly. A brace 65 links the two sides of the framebeneath the carriage assembly to provide greater strength. When thecarriage reaches one extremity of its rectilinear motion parallel to theplane of the core, the air cylinder is actuated by the micro switch andtransfers the reel to the other cylinder whereupon the carriagecontinues in the opposite direction.

FIG. 4 is a cross section of one of the double acting air cylinders usedto transfer the reel. When reel transfer takes place (at either end ofthe carriage rectilinear motion) cam 48 activates micro switch 49 or 50causing compressed air to enter port 68 thereby causing the large piston66 and the smaller piston 67 to move together away from port 68. Thepistons continue to move until the notched axle of the reel assembly 62on the small piston hits its counterpart on the other cylinder. Thisstops the travel of the axle and small piston 67. The larger piston 66and flange 66a attached thereto continue their motion pushing the reelfrom axle 62 onto the axle of the opposite cylinder, thereby effectingreel transfer. The reel is held onto the opposite axle by detents. Airpressure is then returned to port 69, its normal position, by the elapseof dwell time of cam 48 deactivating micro switch 49 or 50. The airforces both pistons to return toward port 68 until they seat. Thispositions the cylinder for the next transfer of the reel. Rotary motionof the reel while in place on the axle 62 is allowed by a needle bearing62a mounted between the axle 62 and the small piston 67.

Further details of the reel assembly are shown in FIG.

- 3. The hole in the center of hub 70 of a housing 71 receives the axleon a piston of the air cylinder (FIG. 2) for mounting the reel assembly.Three spring loaded plungers 120 apart 72, 73 and 74, retain the hub inposition on the piston of the air cylinder by a groove in the aircylinder axle (FIG. 2). Around the periphery of the housing is mountedthe reel 75 which is firmly fixed to the housing. The reel in turn issurrounded by a shroud 5 independently rotatable with respect to thereel which comprises three sections, two solid 76 and 77, and oneslotted 78, to provide for discharge of the wire strand. Portions of themetal are cut away from the housing 71 around the periphery of the hubto lighten the reel assembly. A bearing mounting ring 79 fastened bythree screws 80, 81 and 82 confines ball bearings on which the shroudrotates. The shroud is also fastened to the bearing mounting ring 79 byscrews 83, 84 and 85.

FIG. 3a shows a cross section of the reel assembly perpendicular to itsaxis along line A-A of FIG. 3 through the slotted portion of the shroud.The shroud 5 with its wire discharge slot 780 is mounted by ballbearings 86 inserted in the reel housing by which it is independentlyrotatable with respect to the reel. Reel for holding the strand wire isfixed to the housing 71 by screws 87 and 88. The function of the springloaded plungers 72, 73 and 74 as has been explained is to locate thereel on the piston of the air cylinder and fix it in place.

The apparatus described minimizes distortion of the wire strand bykeeping the reel close to the plane of the core as it proceeds in itsforward and backward motion. There may be for example about inchclearance between the reel and the core. Close proximity provides for amaximum angle between the section of wire strand from the reel to thecore and the plane of the reel. It will be appreciatedthat when the reelis on the inside of the core hoop the distance between the center pointof the reel and the core is considerably greater than the distancebetween said center point and the core when the reel is directly besidethe core or in other words when the axis of the reel is coincident witha point on the axis of the core through its centers of cross sections.

The general operation of the apparatus will now be described for thepreparation of a l 9 cable comprising an annular core of 15.281 in.inside diameter (15 9/32 in. formed from 0.118 in. diameter SAE I008 lowcarbon steel surrounded by 9 lays of strand, each lay wrapping the coreeight times and composed of 0.059 in. diameter (nominal 0.06 in.) SAE1070 bronze dip bead wire, the toal length of strand being 36 ft. 5 in.An end of the aforesaid predetermined length of strand is temporarilyfastened to said core. No permanent connection of strand to core isdesired and to start the process a piece of Mylar tape will suffice tohold the strand on the core and still permit some movement, ifnecessary, to conform to a natural angle of lay for the system. The wireis taped to the core at approximately the desired angle of lay and thetape need not necessarily be removed, but if removal is desired asoluble tape, for example, cellulose acetate tape, may be used. The beltdrive clamping cylinder 6 is then actuated by switch 27 and the core andcarriage put into motion by activating starting switch 8. The rotationof the core pulls wire from the strand supply confined by the reelshroud.

The reel simply floats with respect to the rotation of the core andthere is very little tension on the wrap wire resisting withdrawal bythe rotating core. The slight spring tension under which the wrap wireis confined on the reel provides slight resistance to withdrawal andautomatically tends to control rotation of the reel so that little or nounwinding of wire occurs ahead of that required to wrap the core. Itwill be appreciated that the wrap wire is not really wound around thereel but simply restrained in loops around it in the form of a coil. Theshroud is preferably independently movable with respect to the reel toaid the movement of the wire outlet which must change position as thereel proceeds back and forth.

In the position illustrated in FIG. 1 the reel and supply of strand arein front of the core and the carriage assembly continues to moveparallel with the plane of the bead toward the opening in the bead hoopuntil clearance is provided whereupon the reel shifts to the axle of theopposite air cylinder 41 and moves in the opposite direction on the backside of the bead until clearance is provided for a shift to the front ofthe head again whereupon the carriage assembly again reverses direction.The operation is continued until the strand supply is exhausted and thenthe two ends of strand now constituting the wrap wire are fitted into aferrule crimped in the middle to connect the ends of the wrap wire toprovide the finished bead.

The two ends of wrap wire remaining at the end of the operation requiresome restraint to keep them from lifting from the core but are otherwiseleft floating. The ferrule and its use are well known in the cable beadart and serve to maintain the free ends of the wire in alignment duringthe relative movement of the ends.

It is intended to cover all changes and modifications of the examples ofthe invention herein chosen for purposes of disclosure which do notconstitute departures from the spirit and scope of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. Apparatus for forming a cable bead comprising means for supporting anannular bead core and rotating it about its axis of symmetry,

means for storing a supply of strand in coil form,

means for feeding strand to said core from the supply coil,

means for moving the supply of strand successively about said core withrespect to an axis passing through its centers of cross sections,

means for applying strand to the core at a strain below its resiliencelimit by providing for discharge of strand from the supply coil atpoints which when outside the plane defined by the circumferentialcenter line of the core are always a perpendicular distance from saidplane less than the radius of the strand coil.

2. Apparatus for forming a cable bead comprising means for supporting anannular bead core and rotating it about its axis of symmetry,

means for storing a supply of strand in coil form,

means for feeding strand from the supply to the core substantiallyuntensioned except for its own spring tension,

means for moving the supply of strand successively about the annularcore with respect to an axis passing through its centers of crosssections cooperating with means to maintain a perpendicular to the axisof the supply coil disposed parallel to the plane of moving said suppiyof strand around said core parallel to the plane defined by thecircumferential center line of the core and to provide for discharge ofstrand from the supply coil at points which when outside said centerline plane are always a perpendicular distance from said plane less thanthe radius of the strand coil, said moving means being synchronizcd withrotation of the annular core to apply contiguous strands.

3. Apparatus of claim 2 wherein the storing means includes means forrestraining the strand in reduced coil size.

4. Apparatus of claim 3 wherein the storing means comprises reel andshroud and the motion of the reel is substantially rectilinear.

5. Apparatus of claim 2 which includes means for varying thesynchronization.

6. Method of forming a cable bead which comprises supporting an annularbead core, continuously rotating it about its axis of symmetry, feedingstrand to the rotating core from a supply thereof while moving saidsupply about the annular core with respect to an axis passing throughits centers of cross section, confining the strain of the wirethroughout said moving below its resilience limit and synchronizing thespeed of said moving with the speed of said rotating so as to applycontiguous strands.

7. Method of claim 6 wherein the supply is in coil form and distortionis minimized by maintaining a perpendicular to the axis of the supplycoil disposed parallel to the plane of moving said supply of strandaround said core parallel to the plane defined by the circumferentialcenter line of the core and discharging from the supply coil at pointswhich when outside said center line plane are always a perpendiculardistance from said plane less than the radius of the supply coil.

8. Method of claim 7 wherein the strand supply is confined under its ownspring tension and is fed to the core substantially under said tension.

9. Method of claim 7 wherein the supply comprises a predetermined lengthof strand.

10. Method of claim 7 wherein the rotation of the core removes strandfrom the supply the resistance to removal consisting essentially offorces due to the spring tension of the strand.

1. Apparatus for forming a cable bead comprising means for supporting anannular bead core and rotating it about its axis of symmetry, means forstoring a supply of strand in coil form, means for feeding strand tosaid core from the supply coil, means for moving the supply of strandsuccessively about said core with respect to an axis passing through itscenters of cross sections, means for applying strand to the core at astrain below its resilience limit by providing for discharge of strandfrom the supply coil at points which when outside the plane defined bythe circumferential center line of the core are always a perpendiculardistance from said plane less than the radius of the strand coil. 2.Apparatus for forming a cable bead comprising means for supporting ananNular bead core and rotating it about its axis of symmetry, means forstoring a supply of strand in coil form, means for feeding strand fromthe supply to the core substantially untensioned except for its ownspring tension, means for moving the supply of strand successively aboutthe annular core with respect to an axis passing through its centers ofcross sections cooperating with means to maintain a perpendicular to theaxis of the supply coil disposed parallel to the plane of moving saidsupply of strand around said core parallel to the plane defined by thecircumferential center line of the core and to provide for discharge ofstrand from the supply coil at points which when outside said centerline plane are always a perpendicular distance from said plane less thanthe radius of the strand coil, said moving means being synchronized withrotation of the annular core to apply contiguous strands.
 3. Apparatusof claim 2 wherein the storing means includes means for restraining thestrand in reduced coil size.
 4. Apparatus of claim 3 wherein the storingmeans comprises reel and shroud and the motion of the reel issubstantially rectilinear.
 5. Apparatus of claim 2 which includes meansfor varying the synchronization.
 6. Method of forming a cable bead whichcomprises supporting an annular bead core, continuously rotating itabout its axis of symmetry, feeding strand to the rotating core from asupply thereof while moving said supply about the annular core withrespect to an axis passing through its centers of cross section,confining the strain of the wire throughout said moving below itsresilience limit and synchronizing the speed of said moving with thespeed of said rotating so as to apply contiguous strands.
 7. Method ofclaim 6 wherein the supply is in coil form and distortion is minimizedby maintaining a perpendicular to the axis of the supply coil disposedparallel to the plane of moving said supply of strand around said coreparallel to the plane defined by the circumferential center line of thecore and discharging from the supply coil at points which when outsidesaid center line plane are always a perpendicular distance from saidplane less than the radius of the supply coil.
 8. Method of claim 7wherein the strand supply is confined under its own spring tension andis fed to the core substantially under said tension.
 9. Method of claim7 wherein the supply comprises a predetermined length of strand. 10.Method of claim 7 wherein the rotation of the core removes strand fromthe supply the resistance to removal consisting essentially of forcesdue to the spring tension of the strand.